Guide to setting up A2090a with SCSI2SD

[RobTurbo]

I recently moved my amiga obsession to an A2000 that I bought as non working due to battery leakage, new CPU and kickstart sockets and a bit of a clean up and it's up and running again. There were no expansion cards or drives, just the motherboard (Rev 6, KS 2.04), drive mounting bracket and PSU in a case.

I modified a PC floppy cable to work in the A2000, with a gotek as DF0 and a drive from an external floppy as DF1. For a keyboard I used an A500 keyboard and made an adapter. Next I bought some ram cards (2x2mb) and an A2090a hard disk controller, from Dagger on here, the ram cards worked straight away, the A2090a not quite so simple!

There's not a lot of info on the A2090a, I did look into it before I bought it and fancied the challenge! If you search for info on the A2090a pretty much all you'll come across is the fact it only supports drives up to 256mb, it doesn't support any hard drive tools other than it's own "Prep" and almost every time someone asks for help with it the response is not to bother, get a better card instead!

I bought a SCSI2SD adapter and used a 2gb card for the "drives", I used the software so set the card up as 4 separate 256mb drives, really easy to use, plugged it into the A2090a and that's hardware side done!

*The following is a long story cut short, with all of the re-doing wrong ideas and mistakes removed!*

You will need the following software to do it this way, there may (will) be other ways but this worked for me;

Workbench 2.04 boot and extras disks
A2090 HD Install Disk - it's in the TOSEC archive, probably other places too
Directory Opus - I used v4.11

First boot from a copy of your workbench disk (it's going to get files copied to it), then insert the A2090 HD Install Disk, open it up and run "Install", it'll copy some files to ram (drivers and tools) then ask for your workbench disk, agree with everything it asks you then it will copy the files from ram to your workbench disk, then it will set up the first "drive" which will be DH2, when it asks you to select a drive from the list enter the following details;

Drive type = 0
Number of heads = 8
Number of cylinders = 1024
Number of Sectors per track = 64

Everything else just press enter to choose the default value, when it warns you all the data on the drive will be lost press Y then enter, it'll prep the first drive then tell you to reboot then format DH2:, so reboot with your workbench disk, open a shell window and type;

Format DRIVE DH2: NAME Workbench QUICK

Followed by enter, it'll format the drive and name it Workbench, obviously you can call it whatever you want! For the next part there maybe a shell command to do it but I don't know it so I used Directory Opus! In Directory Opus, open SYS: in one window and DH2: in the other window, with the SYS: window selected click "All" then "Copy", this will copy all of your Workbench disk to the hard drive, once it's done you can put your Workbench extras disk in and copy the contents to the hard drive as well.

Now you can remove all floppys/usb stick from gotek and reboot, it should boot straight into Workbench, if your SD card is only big enough for one 256mb "drive" or you only want one drive you're done, if you want to use the rest of the "drives" keep reading.

To access the rest of the "drives" you need to prep them, then format them, first you need to edit your mount list, open a shell window and type;

ED DEVS:MountList

Followed by enter, add the following lines, right at the top will do;

RES3: Device = hddisk.device
Unit = 4
Flags = 0
Surfaces = 8
BlocksPerTrack = 64
Reserved = 0
Interleave = 0
LowCyl = 0 ; HighCyl = 1
Buffers = 5
BufMemType = 0
#

RES4: Device = hddisk.device
Unit = 5
Flags = 0
Surfaces = 8
BlocksPerTrack = 64
Reserved = 0
Interleave = 0
LowCyl = 0 ; HighCyl = 1
Buffers = 5
BufMemType = 0
#

RES5: Device = hddisk.device
Unit = 6
Flags = 0
Surfaces = 8
BlocksPerTrack = 64
Reserved = 0
Interleave = 0
LowCyl = 0 ; HighCyl = 1
Buffers = 5
BufMemType = 0
#

Then save the file and close the editor, back in the shell window type;

Mount RES3: from DEVS:MountList
Mount RES4: from DEVS:MountList
Mount RES5: from DEVS:MountList
Prep RES3:
Prep RES4:
Prep RES5:

Press enter after each line, each of the Prep commands will ask for the drive information, it's the same as setting up the first drive;

Drive type = 0
Number of heads = 8
Number of cylinders = 1024
Number of Sectors per track = 64

Default for everything else, make sure you pick Y on the last question otherwise it won't do anything. Once you've successfully prepped all 3 drives you can restart again, now you can format each drive from a shell window by typing;

Format DRIVE DH*: NAME "drive name" QUICK

Replace * with 3, 4 or 5 and "drive name" with whatever you want to call each drive, don't forget QUICK at the end unless you've got a lot of time on your hands!

I assume you could do the same with other versions of Workbench depending on your kickstart version, I believe it has to be at least 1.3 for autoboot to work. Next I need to see if I can figure out how to get rid of the 256mb limit.

[Arnie]

The bit that I don't understand is, if you have mounted the drives RES*:, how can you format drive DH*:?

What are the pro's & cons of mounting 4 drives vs creating 4 partitions?

[RobTurbo]

RES* is the first 2 cylinders of each drive, they are reserved to hold the drive info, the MountList entries are defining the first 2 cylinders as RES* so that you can mount it, when you run Prep it is storing the drive info into this first tiny partition, at boot the card then reads the drive data from this RES* partition of each drive and makes it visible in Workbench.

The reason for 4 drives instead of partitions is the A2090a has a drive limit of 256mb, that means anything past 524288 sectors will crash, which means after the first 256mb of any drive is useless, all partitions have to be within that size, that's where using a SCSI2SD is a bonus because it can split the card into up to 4 virtual drives, each with their own first 524288 sectors.

[Arnie]

Thanks for explaining it. I didn't know that.

I also use the SCSI2SD card in a CDTV, it works really well.

[Jope]

At least you had the autoboot version. The much more common A2090 without the second A is definitely not worth anyone's time. :-)

There is also a patch to get it to support over 256MB drives, apparently it was a rather simple mistake in the ROM.

http://www.lysator.liu.se/amiga/hard/guide/A2090.guide has the patch uuencoded inside it.

[RobTurbo]

I've got the patch but the guide says "To use this patch you _must_ have a machine using a 68020/68030/68040 with a MMU present", which I don't have, so "the only option is to actually burn new EPROMs for the 2090a."

The problem is there's no info on how to burn the new EPROMs, I'd guess that the problem is only in one EPROM, I'll need to find a spare to practice with, then I need to find out how to patch the file then burn it back to the EPROM, I hope my willem can read/write whatever EPROM it is.

[Jope]

The willem can do it, yes.

[RobTurbo]

Have you modified the EPROM on one of these before? I could do with some pointers, I haven't come across any info at all on how to patch the actual EPROM.

[Jope]

I have not. If I remember, I'll take a look later.

[RobTurbo]

Is there any way of saving the patched rom from memory within workbench?

I'm thinking if I can make an A2000 config for winuae, with an 020/030/040 with MMU, use the fix2090a patch, then save the rom I can burn it to eprom(s) for the card.

Edit:

I've successfully patched the rom in memory using winuae, just need a way to copy it to a file!

[RobTurbo]

I've sorted it, ended up going a different route. The EPROMs that need patching are U50 (HI) and U51 (LO), I joined them together using winhex (unify bytewise), disassembled the resulting file using IRA (with -a so I can see what the code looks like in hex), found the code that needed modifying and copied it into a new file so I didn't have to search through code that I don't need, then changed it to what it should be, saved it then compiled it with vasm, now I know what the code I need looks like in hex so all I had to do was search the combined file to find the area that needed changing, then edited, saved, split back into two (dissect bytewise), then wrote the files back to EPROMs.

I didn't want to erase the EPROMs from the card (both 27c64) before I knew it worked, so I had a rake around and found a 27c512 on an old motherboard and a 27c256 in an ECU I don't need anymore so I copied the HI file 8 times and the LO file 4 times, wrote them, fitted them, changed the SCSI2SD settings so the last "drive" was 500mb, re-prepped RES5: with double the cylinders, restarted and formatted DH5:, all went well and I now have a fully functional 487mb "drive"

Now I know it works I'll erase the original EPROMs and write the new files to them, if anyone want's the patched files I don't mind sharing!! Now off to do some A2000 keyboard research...

[Arnie]

That's pretty impressive, well done

[mark_k]

Links to A2090/2092 user manuals can be found in this thread.

[powrslave]

Check it out Rob
http://www.thingiverse.com/thing:1131419

[Jope]

Good show, I admit I forgot all about this. :-)

Dear RobTurbo,

your post should fit the issue I have with my old A2000 Rev 6 - ROM 2.04, with a A2090A controller connected to a 20Mb Epson HDD, no longer working.

I've been suggested to buy a SCSI-2-SD adapter.

I would appreciate if you can answer some quick questions:

- which SCSI2SD model you purchased?
- do I have to mind about U50 (HI) and U51 (LO) patching even if 256Mb size limit for partitions is not an issue to me (I think this size will surely fit a WB 2.1/3.1 installation)?
- can I use SD bigger than 2 Gb (since this size is now difficult to find out)?

Thank you in advance

BR

[aperez]

Originally Posted by Odusseus71

Dear RobTurbo,

your post should fit the issue I have with my old A2000 Rev 6 - ROM 2.04, with a A2090A controller connected to a 20Mb Epson HDD, no longer working.

I've been suggested to buy a SCSI-2-SD adapter.

I would appreciate if you can answer some quick questions:

I can do that; I'm the person who has the V5 boards manufactured in large quantities. Michael McMaster/CodeSrc, the creator, no longer sells V5 boards, as he is focused on improving V6 for now.

Originally Posted by Odusseus71

- which SCSI2SD model you purchased?

He's probably using V5a. You want V5a. There are only two models available today, V5 and V6. V6 is significantly more expensive, due to a number of factors.

Originally Posted by Odusseus71

- do I have to mind about U50 (HI) and U51 (LO) patching even if 256Mb size limit for partitions is not an issue to me (I think this size will surely fit a WB 2.1/3.1 installation)?

Nope!

Originally Posted by Odusseus71

- can I use SD bigger than 2 Gb (since this size is now difficult to find out)?

Thank you in advance

BR

You can use any size microSD card you want, including significantly larger.

Dear aperez,

thank you very much for your feedback.

I would appreciate if you can share with me some more suggestions.

Unfortunately, I can check my A2000 periodically and I missed to notice that my A2090(A) has no boot roms U50 and U51 at all, being the U36 the only one present on the board.

That should mean no autoboot from SD even if the SCSI2SD adapter is succesfully configured.

Therefore I've spent some time and money and catched from ebay two further SCSI controllers (to be delivered):

- a german MacroSystem Evolution 2000

- an A2091, with boot roms

In your opinion, which one should be the best companion for SCSI2SD (V5)?

Can I apply same Rob's procedure as per A2090A or is there a different approach?

My last Amiga experience (WB 2.1 installation on a 20 MBytes ST-506 HDD) is aged 28, so that any hint is really helpful.

Thank you in advance for your help

BR

Marco

[Jope]

The A2091 is a very nice SCSI card, I recommend that. DMA transfers! <3

Thank You!

I guess DMA lower than 3 is a suggested setting, but need to understand whee to set.

I have to understand the whole installation process, actually.

From Rob's email I got the basics, when the HDD is a SCSI2HD adapter, are:

1) boot from a workbench disk (a copy of)
2) run "Install" from Controller related Install Disk, that will transfer some files to WB disk and will set up DH2 as the first "drive"
3) input proper drive parameters: Drive type = 0, Number of heads = 8, Number of cylinders = 1024, Number of Sectors per track = 64 (need to be adapted to size bigger than 256mb, that should not be longer a limitation on A2091)
4) reboot from WB disk and format DH2 by CLI
5) copy the whole content of both WB (Install?) and Extras disk to DH2

Please, tell me if I'm going in the right direction.

Thanks a lot